The overall aim of this research continues to be a comprehensive evaluation of behavioral, neurochemical and morphological changes induced by repeated administration of psychomotor stimulant drugs. To this end a group of investigators drawn from different disciplines have begun to broaden the experimental approach in investigating irreversible changes in brain catecholamines that occur as a result of repeated administration of methamphetamine. The primary thrust of research over the past year has been to broaden the investigations of the behavioral consequences of prolonged methamphetamine administration in the rhesus monkey and also to determine whether or not the same irreversible changes in brain catecholamines that occurred in the rhesus monkey also occur in other species. The latter work has entailed using albino rats as experimental subjects. BIBLIOGRAPHIC REFERENCES: G.T. Shybut, W.R. Richter, and C.R. Schuster; Absence of pathological changes following intravenous methamphetamine and intra-arterial iothalamate meglumine. Research Communications in Chemical Pathology and Pharmacology, 15, #1, Sept. 1976. Seiden, L.S., Fischman, M.W., and Schuster, C.R.; Long-term methamphetamine induced changes in brain catecholamines in tolerant rhesus monkeys. Drug and Alcohol Dependence, 1, 215-219, 1975-76.